Pub Date : 2021-08-20DOI: 10.3161/00016454AO2021.56.1.003
S. Arnold, M. Weaver, K. McGraw
Abstract. Urbanization presents wildlife with many novel environmental challenges and opportunities, including navigating new physical structures and exploiting unique food bases. Thus, animal species that persist or thrive in urban environments may have superior cognitive abilities that allow them to navigate and solve anthropogenic problems. Prior studies have shown neural and behavioral differences between animals inhabiting urban and rural environments, but few have tested cognition-related behavioral responses of animals in an urban context. We administered a novel foraging challenge to caged male House Finches Haemorhous mexicanus — a successful urban and native desert species in the southwestern United States — captured from two urban and two rural locations to examine population differences in problem solving. This task involved opening a tin lid that was slid over the bird's normal small food dish and left only slightly ajar (with no food visible). Male House Finches display exaggerated, sexually selected plumage color that is dependent on diet, so we also tested the hypothesis that more colorful males can better solve foraging problems. We found no differences in problem solving success between urban and rural birds. However, among rural birds, we found that redder males were more likely to solve the foraging task than less-red males. Also, birds that lost more mass during the study were more likely to solve the task, but this was only true among less colorful birds. Our results are consistent with the hypothesis that plumage redness reveals foraging skill in House Finches found in their native environment.
{"title":"Ornamental Plumage Coloration Interacts with Habitat Urbanization to Predict Problem-Solving in the House Finch Haemorhous mexicanus","authors":"S. Arnold, M. Weaver, K. McGraw","doi":"10.3161/00016454AO2021.56.1.003","DOIUrl":"https://doi.org/10.3161/00016454AO2021.56.1.003","url":null,"abstract":"Abstract. Urbanization presents wildlife with many novel environmental challenges and opportunities, including navigating new physical structures and exploiting unique food bases. Thus, animal species that persist or thrive in urban environments may have superior cognitive abilities that allow them to navigate and solve anthropogenic problems. Prior studies have shown neural and behavioral differences between animals inhabiting urban and rural environments, but few have tested cognition-related behavioral responses of animals in an urban context. We administered a novel foraging challenge to caged male House Finches Haemorhous mexicanus — a successful urban and native desert species in the southwestern United States — captured from two urban and two rural locations to examine population differences in problem solving. This task involved opening a tin lid that was slid over the bird's normal small food dish and left only slightly ajar (with no food visible). Male House Finches display exaggerated, sexually selected plumage color that is dependent on diet, so we also tested the hypothesis that more colorful males can better solve foraging problems. We found no differences in problem solving success between urban and rural birds. However, among rural birds, we found that redder males were more likely to solve the foraging task than less-red males. Also, birds that lost more mass during the study were more likely to solve the task, but this was only true among less colorful birds. Our results are consistent with the hypothesis that plumage redness reveals foraging skill in House Finches found in their native environment.","PeriodicalId":50888,"journal":{"name":"Acta Ornithologica","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45245024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-08-20DOI: 10.3161/00016454AO2021.56.1.007
I. Mytiai, O. V. Shatkovska, M. Ghazali
Abstract. Despite a huge diversity of egg shapes among birds, similar egg shapes occur in species that differ in habitats and are not phylogenetically closely related; this indicates the presence of factors limiting the egg shape variability. We assume that one of these factors is a general pattern of egg shape change across all birds. We tested a hypothesis of allometric patterns of egg morphometric traits (radii of blunt end (infundibular zone, ri), pointed end (cloacal zone, rc), lateral zone (rl) and maximum diameter (D)) scaling against egg length (L). Phylogenetic allometric analysis was applied. We also studied hierarchical distribution of variation in egg traits at different taxonomic levels in order to determine the degree of egg shape variability on each of them. We revealed allometric patterns in the scaling of egg traits: D and ri scaled against L with negative allometry, while rc and rl were positively allometric. A high degree of covariation was observed between the length and diameter, radii of the lateral and infundibular zones, i.e. traits that are associated with the overall size of an egg, the degree of its elongation, and the shape of infundibular zone. Evolutionary correlation between L and rc was rather low. The greatest variation of egg traits resided at the level of orders. The identified general trends in egg shape variation are realized on the basis of various groups of birds in phylogenetic and ecological sense that assume the influence of these factors on the bird's egg shape.
{"title":"Allometry of Egg Size as a Factor Influencing Egg Shape in Birds","authors":"I. Mytiai, O. V. Shatkovska, M. Ghazali","doi":"10.3161/00016454AO2021.56.1.007","DOIUrl":"https://doi.org/10.3161/00016454AO2021.56.1.007","url":null,"abstract":"Abstract. Despite a huge diversity of egg shapes among birds, similar egg shapes occur in species that differ in habitats and are not phylogenetically closely related; this indicates the presence of factors limiting the egg shape variability. We assume that one of these factors is a general pattern of egg shape change across all birds. We tested a hypothesis of allometric patterns of egg morphometric traits (radii of blunt end (infundibular zone, ri), pointed end (cloacal zone, rc), lateral zone (rl) and maximum diameter (D)) scaling against egg length (L). Phylogenetic allometric analysis was applied. We also studied hierarchical distribution of variation in egg traits at different taxonomic levels in order to determine the degree of egg shape variability on each of them. We revealed allometric patterns in the scaling of egg traits: D and ri scaled against L with negative allometry, while rc and rl were positively allometric. A high degree of covariation was observed between the length and diameter, radii of the lateral and infundibular zones, i.e. traits that are associated with the overall size of an egg, the degree of its elongation, and the shape of infundibular zone. Evolutionary correlation between L and rc was rather low. The greatest variation of egg traits resided at the level of orders. The identified general trends in egg shape variation are realized on the basis of various groups of birds in phylogenetic and ecological sense that assume the influence of these factors on the bird's egg shape.","PeriodicalId":50888,"journal":{"name":"Acta Ornithologica","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49100785","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-08-20DOI: 10.3161/00016454AO2021.56.1.008
Paula M. Orozco-Valor, J. Grande
Abstract. Agricultural expansion at the expense of natural habitats and the intensification processes in agricultural production are globally among the main causes of biodiversity and ecosystem services loss at large scale. This process can completely alter food provision for birds and have negative consequences for their diet and breeding performance. Under the hypothesis that changes in land use limit food resources for raptors, our aim was to analyze variation in nestling diet between natural areas and areas with different degrees of agricultural intensification (natural forest, traditional farmland, intensive farmland) in a population of American Kestrel Falco sparverius breeding in nest boxes and cavities. Through the analysis of pellets and prey remains collected during the reproductive season of 2012–2013 we found no differences in diet diversity among areas and the diet in the three areas was monopolized by arthropods. However, the diet did change in composition between areas. Numerically, Orthoptera dominated the diet in the three areas, although with a higher percentage in the forest area. The frequency of vertebrate consumption was affected positively by the area occupied by natural forest and stubble, while the soybean cover affected the consumption in a negative way. In both agricultural areas, the diet was complemented with different groups of arthropods suggesting that changes in land use generate a functional response in the American Kestrel that is able to take advantage of available resources in each sampling area. Long-term analysis of diet variation within the framework of agricultural intensification and its relation with demographic parameters and individual performance will allow to evaluate the impact of this variation in the diet on kestrels.
{"title":"Diet Variation of a Generalist Predator, the American Kestrel Falco sparverius, in a Gradient of Agricultural Intensification in Central Argentina","authors":"Paula M. Orozco-Valor, J. Grande","doi":"10.3161/00016454AO2021.56.1.008","DOIUrl":"https://doi.org/10.3161/00016454AO2021.56.1.008","url":null,"abstract":"Abstract. Agricultural expansion at the expense of natural habitats and the intensification processes in agricultural production are globally among the main causes of biodiversity and ecosystem services loss at large scale. This process can completely alter food provision for birds and have negative consequences for their diet and breeding performance. Under the hypothesis that changes in land use limit food resources for raptors, our aim was to analyze variation in nestling diet between natural areas and areas with different degrees of agricultural intensification (natural forest, traditional farmland, intensive farmland) in a population of American Kestrel Falco sparverius breeding in nest boxes and cavities. Through the analysis of pellets and prey remains collected during the reproductive season of 2012–2013 we found no differences in diet diversity among areas and the diet in the three areas was monopolized by arthropods. However, the diet did change in composition between areas. Numerically, Orthoptera dominated the diet in the three areas, although with a higher percentage in the forest area. The frequency of vertebrate consumption was affected positively by the area occupied by natural forest and stubble, while the soybean cover affected the consumption in a negative way. In both agricultural areas, the diet was complemented with different groups of arthropods suggesting that changes in land use generate a functional response in the American Kestrel that is able to take advantage of available resources in each sampling area. Long-term analysis of diet variation within the framework of agricultural intensification and its relation with demographic parameters and individual performance will allow to evaluate the impact of this variation in the diet on kestrels.","PeriodicalId":50888,"journal":{"name":"Acta Ornithologica","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46031179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-03-19DOI: 10.3161/00016454AO2020.55.2.002
M. Goretskaia, Eldar Rakhimberdiev, S. Naidenko, V. Moskalenko, E. Veselovskaya, V. Gavrilov, E. Vostretsova, I. Beme
Abstract. Testosterone may affect many aspects of passerine maturation including the expression of plumage coloration and spring migration in adult birds. However, how the testosterone level changes during bird development is not well known. We compared the testosterone profile during juvenile development of a sexually dimorphic species, the Blackcap Sylvia atricapilla, and a monomorphic species, the Wood Warbler Phylloscopus sibilatrix. We first tested whether testosterone influences plumage coloration and increases at the onset of molt in males of the dimorphic but not the monomorphic species. We found that a testosterone level increase occurred in both sexes and species during later stages of molt, and thus was not related to male plumage coloration. We also investigated whether the increase in testosterone level coincides with juvenile dispersal. If testosterone affects dispersal behavior in these species, both sexes should show an elevated testosterone level during dispersal, but this increase should occur earlier in the Wood Warbler, which disperses earlier than the Blackcap. In juvenile Blackcaps, the increase in testosterone level occurred on the 43–68th day after hatching, while in Wood Warblers it occurred on the 32–36th day (i.e. 11–32 days earlier). The increase in testosterone level coincided with the onset of the post-juvenile dispersal in both species. This study provides the first direct evidence of a testosterone level increase during juvenile development in two free-living migratory birds. While not correlated with species plumage coloration, this increase might affect other aspects of behavior, e.g. juvenile dispersal.
{"title":"Testosterone Increase in Free-Living Young Blackcaps Sylvia atricapilla and Wood Warblers Phylloscopus sibilatrix During Post-Juvenile Molt with Possible Implications for Juvenile Dispersal","authors":"M. Goretskaia, Eldar Rakhimberdiev, S. Naidenko, V. Moskalenko, E. Veselovskaya, V. Gavrilov, E. Vostretsova, I. Beme","doi":"10.3161/00016454AO2020.55.2.002","DOIUrl":"https://doi.org/10.3161/00016454AO2020.55.2.002","url":null,"abstract":"Abstract. Testosterone may affect many aspects of passerine maturation including the expression of plumage coloration and spring migration in adult birds. However, how the testosterone level changes during bird development is not well known. We compared the testosterone profile during juvenile development of a sexually dimorphic species, the Blackcap Sylvia atricapilla, and a monomorphic species, the Wood Warbler Phylloscopus sibilatrix. We first tested whether testosterone influences plumage coloration and increases at the onset of molt in males of the dimorphic but not the monomorphic species. We found that a testosterone level increase occurred in both sexes and species during later stages of molt, and thus was not related to male plumage coloration. We also investigated whether the increase in testosterone level coincides with juvenile dispersal. If testosterone affects dispersal behavior in these species, both sexes should show an elevated testosterone level during dispersal, but this increase should occur earlier in the Wood Warbler, which disperses earlier than the Blackcap. In juvenile Blackcaps, the increase in testosterone level occurred on the 43–68th day after hatching, while in Wood Warblers it occurred on the 32–36th day (i.e. 11–32 days earlier). The increase in testosterone level coincided with the onset of the post-juvenile dispersal in both species. This study provides the first direct evidence of a testosterone level increase during juvenile development in two free-living migratory birds. While not correlated with species plumage coloration, this increase might affect other aspects of behavior, e.g. juvenile dispersal.","PeriodicalId":50888,"journal":{"name":"Acta Ornithologica","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48294147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-03-19DOI: 10.3161/00016454AO2020.55.2.010
D. Deeming, Eve Humphreys
Abstract. Incubation of eggs and nestlings is energetically costly and may be affected by the amount of thermal insulation the surrounding nest provides. In many small passerine species, animal-derived materials, i.e., feathers and hair, are often used in the nest lining where, presumably, their lower thermal conductance offers better insulation. A previous study that involved partial deconstruction of thrush nests revealed that different parts of the nest confer different levels of insulation. The present study examined the insulatory values of Common Chaffinch Fringilla coelebs nests because of the high proportion of animal-derived materials in their cup lining but not the outer nest. Insulatory values and cooling rates of temperature loggers inside the cup were determined for whole nests and then only the cup lining. There were no significant relationships between nest measurements and measures of thermal insulation. However, removal of the outer nest wall reduced the insulatory value by around 10% despite the cup lining being less than half the thickness of the complete nest wall and the cup lining being only a third of the total nest mass. Differential placement of animal-derived materials within the cup lining of Common Chaffinch nests means that the birds seem to be able to confer a high level of insulation without expending too much energy searching for a large mass of particular nest materials.
{"title":"Insulation of Common Chaffinch Fringilla coelebs Nests is Largely Driven by Animal-Derived Materials in the Cup Lining","authors":"D. Deeming, Eve Humphreys","doi":"10.3161/00016454AO2020.55.2.010","DOIUrl":"https://doi.org/10.3161/00016454AO2020.55.2.010","url":null,"abstract":"Abstract. Incubation of eggs and nestlings is energetically costly and may be affected by the amount of thermal insulation the surrounding nest provides. In many small passerine species, animal-derived materials, i.e., feathers and hair, are often used in the nest lining where, presumably, their lower thermal conductance offers better insulation. A previous study that involved partial deconstruction of thrush nests revealed that different parts of the nest confer different levels of insulation. The present study examined the insulatory values of Common Chaffinch Fringilla coelebs nests because of the high proportion of animal-derived materials in their cup lining but not the outer nest. Insulatory values and cooling rates of temperature loggers inside the cup were determined for whole nests and then only the cup lining. There were no significant relationships between nest measurements and measures of thermal insulation. However, removal of the outer nest wall reduced the insulatory value by around 10% despite the cup lining being less than half the thickness of the complete nest wall and the cup lining being only a third of the total nest mass. Differential placement of animal-derived materials within the cup lining of Common Chaffinch nests means that the birds seem to be able to confer a high level of insulation without expending too much energy searching for a large mass of particular nest materials.","PeriodicalId":50888,"journal":{"name":"Acta Ornithologica","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48649182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-03-19DOI: 10.3161/00016454AO2020.55.2.003
N. V. Marinero, J. L. Navarro, M. Martella
Abstract. In herbivores, habitat preference is influenced by resource availability, which is most evident in desert ecosystems. The desert puna is a South American environment dominated by grassy steppes with local grassy cushion plants associated with moist soil conditions, which form the habitat called ‘vegas'. In this environment, Puna Rhea Rhea tarapacencis has a strongly selective foraging strategy towards plant species that are in low abundance but that exhibit low contents of secondary compounds, fiber, or both. This contrasts with other generalist herbivores of arid environments, which prefer plant species with high fiber content and are highly abundant. We determined habitat use by Rheas in three habitat types: foothills, valley and vegas; and provided evidence of their feeding habitat preferences. From 2011 to 2014, we estimated density of birds and environmental variables such as total plant cover and abundance of total food, preferred foods and non-preferred foods. In particular, the density was estimated indirectly based on counting and collecting feces of the birds in transects. We analyzed the effect of the habitat type and environment variables on bird density; and compared the environmental variables among habitats. Puna Rheas used the three habitats, but fecal records were very scarce in vegas. The density was higher in foothills than in the valley (0.45 and 0.01 inds/km2, respectively), increased with higher abundance of the preferred foods and declined with increased non-preferred foods. The foothills were preferred as they had the highest abundance of the preferred foods and the non-preferred foods were similarly abundant in foothills and valley. The vegas had the highest total plant cover and the lowest abundance of all food species consumed by the Rheas. Therefore, the abundance of preferred foods, which have the best nutritional quality, represents a good predictor of habitat preference and, possibly, an essential resource during the life cycle of the Puna Rhea.
{"title":"Foraging Habitat Preferences of a Selective Herbivorous Bird, the Puna Rhea Rhea tarapacencis in the Desert Puna, Midwestern Argentina","authors":"N. V. Marinero, J. L. Navarro, M. Martella","doi":"10.3161/00016454AO2020.55.2.003","DOIUrl":"https://doi.org/10.3161/00016454AO2020.55.2.003","url":null,"abstract":"Abstract. In herbivores, habitat preference is influenced by resource availability, which is most evident in desert ecosystems. The desert puna is a South American environment dominated by grassy steppes with local grassy cushion plants associated with moist soil conditions, which form the habitat called ‘vegas'. In this environment, Puna Rhea Rhea tarapacencis has a strongly selective foraging strategy towards plant species that are in low abundance but that exhibit low contents of secondary compounds, fiber, or both. This contrasts with other generalist herbivores of arid environments, which prefer plant species with high fiber content and are highly abundant. We determined habitat use by Rheas in three habitat types: foothills, valley and vegas; and provided evidence of their feeding habitat preferences. From 2011 to 2014, we estimated density of birds and environmental variables such as total plant cover and abundance of total food, preferred foods and non-preferred foods. In particular, the density was estimated indirectly based on counting and collecting feces of the birds in transects. We analyzed the effect of the habitat type and environment variables on bird density; and compared the environmental variables among habitats. Puna Rheas used the three habitats, but fecal records were very scarce in vegas. The density was higher in foothills than in the valley (0.45 and 0.01 inds/km2, respectively), increased with higher abundance of the preferred foods and declined with increased non-preferred foods. The foothills were preferred as they had the highest abundance of the preferred foods and the non-preferred foods were similarly abundant in foothills and valley. The vegas had the highest total plant cover and the lowest abundance of all food species consumed by the Rheas. Therefore, the abundance of preferred foods, which have the best nutritional quality, represents a good predictor of habitat preference and, possibly, an essential resource during the life cycle of the Puna Rhea.","PeriodicalId":50888,"journal":{"name":"Acta Ornithologica","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48010207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-03-19DOI: 10.3161/00016454AO2020.55.2.004
P. Matyjasiak, G. Bazzi, D. Rubolini
Abstract. Migratory birds have evolved the ability to accumulate fat reserves to fuel their migratory journeys. However, increased fuel load leads to an increased body mass, which is expected to impair flight performance and increase predation risk. Results of previous research are contradictory, with some studies reporting detrimental effects of fat load on flight performance, while others showing no such influences. Furthermore, no studies have investigated the relationship between fat load and flight performance in obligate aerial insectivores, which are known to accumulate only moderate fat loads while migrating overland and not crossing wide ecological barriers such as oceans or deserts. In this study we investigated the inter-individual variation in short-term flight performance (flight manoeuvrability, velocity and acceleration) in juvenile Barn Swallows Hirundo rustica in relation to fat load in Poland (central Europe), during the initial stages of autumn southward migration. We evaluated individual swallow fat loads by means of a Total Body Electrical Conductivity (TOBEC) scanner. In order to evaluate short-term flight performance in a standardised manner we used flight tunnels. We controlled statistically for the independent effect of wing morphology, which can be expected to influence flight performance. Juvenile fat loads were on average 7.5% (range 0.2–20.5) of lean body mass, but we found no negative effect of the fat mass on short-term flight performance traits. Individuals with larger fat mass reached higher velocity compared to leaner ones, which is in line with theoretical expectations. However, fat mass did not significantly predict flight manoeuvrability or acceleration. The results indicate that relatively small fat loads accumulated by juvenile Barn Swallows during overland migration do not impair short-term flight performance.
{"title":"Flight Performance of Migrating Juvenile Barn Swallows Hirundo rustica in Relation to Fat Load and Wing Morphology","authors":"P. Matyjasiak, G. Bazzi, D. Rubolini","doi":"10.3161/00016454AO2020.55.2.004","DOIUrl":"https://doi.org/10.3161/00016454AO2020.55.2.004","url":null,"abstract":"Abstract. Migratory birds have evolved the ability to accumulate fat reserves to fuel their migratory journeys. However, increased fuel load leads to an increased body mass, which is expected to impair flight performance and increase predation risk. Results of previous research are contradictory, with some studies reporting detrimental effects of fat load on flight performance, while others showing no such influences. Furthermore, no studies have investigated the relationship between fat load and flight performance in obligate aerial insectivores, which are known to accumulate only moderate fat loads while migrating overland and not crossing wide ecological barriers such as oceans or deserts. In this study we investigated the inter-individual variation in short-term flight performance (flight manoeuvrability, velocity and acceleration) in juvenile Barn Swallows Hirundo rustica in relation to fat load in Poland (central Europe), during the initial stages of autumn southward migration. We evaluated individual swallow fat loads by means of a Total Body Electrical Conductivity (TOBEC) scanner. In order to evaluate short-term flight performance in a standardised manner we used flight tunnels. We controlled statistically for the independent effect of wing morphology, which can be expected to influence flight performance. Juvenile fat loads were on average 7.5% (range 0.2–20.5) of lean body mass, but we found no negative effect of the fat mass on short-term flight performance traits. Individuals with larger fat mass reached higher velocity compared to leaner ones, which is in line with theoretical expectations. However, fat mass did not significantly predict flight manoeuvrability or acceleration. The results indicate that relatively small fat loads accumulated by juvenile Barn Swallows during overland migration do not impair short-term flight performance.","PeriodicalId":50888,"journal":{"name":"Acta Ornithologica","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49657008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-03-19DOI: 10.3161/00016454AO2020.55.2.005
D. F. Perrella, P. Zima, M. Francisco
Abstract. In tropical forests many forest-dwelling non-aquatic passerines build nests by forest streams. It has been proposed that this behavior protects the nest from predators. However, this hypothesis has been rarely tested, and relevant aspects of the relationships between nesting birds and forest streams are to be studied. Firstly, it is not clear whether tropical forest understory passerines can indeed select stream banks for nest construction, as researchers often use forest streams as pathways, which could cause the false impression that nests of certain species are more frequently found near water. Secondly, it is expected that if birds select stream banks for nest construction, they will choose nest spots with characteristics that could increase nest survival. We studied nest site selection in two Atlantic Forest birds: the Blue Manakin Chiroxiphia caudata and the Star-throated Antwren Rhopias gularis. Nests were searched near and far from water, and a number of stream characteristics, including width, depth, water speed and water sound were compared between nest sites and random sites chosen upstream or downstream. Finally, we addressed whether stream variables could explain nest daily survival rate (DSR). Nests of both species were found only near or over water, and the average DSR was 0.975 for the Blue Manakin and 0.972 for the Star-throated Antwren. Our results provided support for the "aqua-phobic nest predator hypothesis", since we found a positive correlation between DSR and stream depth for the Star-throated Antwren and a negative correlation between nest distance from water and DSR for the Blue Manakin. However, stream parameters were not among the main variables explaining nest site selection along streams. This suggests that partial isolation provided by forest streams may reduce nest predation and can drive these species to use stream banks for nesting. The main predators of Blue Manakin nests were birds (80% of filmed predation events), whereas nests of Star-throated Antwren were preyed upon mostly by mammals (54.5% of the records).
{"title":"Nest Site Selection Along Forest-Streams by Two Forest-Dwelling Neotropical Passerines","authors":"D. F. Perrella, P. Zima, M. Francisco","doi":"10.3161/00016454AO2020.55.2.005","DOIUrl":"https://doi.org/10.3161/00016454AO2020.55.2.005","url":null,"abstract":"Abstract. In tropical forests many forest-dwelling non-aquatic passerines build nests by forest streams. It has been proposed that this behavior protects the nest from predators. However, this hypothesis has been rarely tested, and relevant aspects of the relationships between nesting birds and forest streams are to be studied. Firstly, it is not clear whether tropical forest understory passerines can indeed select stream banks for nest construction, as researchers often use forest streams as pathways, which could cause the false impression that nests of certain species are more frequently found near water. Secondly, it is expected that if birds select stream banks for nest construction, they will choose nest spots with characteristics that could increase nest survival. We studied nest site selection in two Atlantic Forest birds: the Blue Manakin Chiroxiphia caudata and the Star-throated Antwren Rhopias gularis. Nests were searched near and far from water, and a number of stream characteristics, including width, depth, water speed and water sound were compared between nest sites and random sites chosen upstream or downstream. Finally, we addressed whether stream variables could explain nest daily survival rate (DSR). Nests of both species were found only near or over water, and the average DSR was 0.975 for the Blue Manakin and 0.972 for the Star-throated Antwren. Our results provided support for the \"aqua-phobic nest predator hypothesis\", since we found a positive correlation between DSR and stream depth for the Star-throated Antwren and a negative correlation between nest distance from water and DSR for the Blue Manakin. However, stream parameters were not among the main variables explaining nest site selection along streams. This suggests that partial isolation provided by forest streams may reduce nest predation and can drive these species to use stream banks for nesting. The main predators of Blue Manakin nests were birds (80% of filmed predation events), whereas nests of Star-throated Antwren were preyed upon mostly by mammals (54.5% of the records).","PeriodicalId":50888,"journal":{"name":"Acta Ornithologica","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42873590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-03-19DOI: 10.3161/00016454AO2020.55.2.011
José M. Fernández-García, H. Robles
Abstract. Citizen science (i.e. monitoring or research schemes with volunteer participation in data collection) is becoming an increasingly used tool that may yield reliable estimates of species distribution ranges. In 2017 and 2018, we assessed the fine-grain distribution and habitat use of the Middle Spotted Woodpecker in the Basque Country (N Spain) by combining two citizen science approaches: opportunistic observations gathered from internet collaborative databases, and standardised records collected by volunteers trained with a species-specific fieldwork protocol. Six out of the thirty-four opportunistic observations were located out of previously known distribution ranges. Because the reliability of those observations was difficult to assess, opportunistic observations should be validated to avoid false positives. As for the species-specific approach, Middle Spotted Woodpecker occurrence was examined by conducting itineraries with point counts and audio-stimulation, sampled twice during the pre-breeding season, in 95 UTM units of 1 km2. Woodpeckers were recorded in 29 of those units. In combination with recent species-specific studies, our results show that Middle Spotted Woodpeckers occurred mainly in a core, continuous range (69 positive units in and around the Izki forest) and in two smaller ranges (6 units in Montes de Vitoria and 5 units in Sierra de Entzia). Out of previously known distribution ranges, the species-specific approach showed that woodpecker occurrence was negatively affected by the distance to the core Izki forest and, to a lesser extent, positively influenced by the tree basal area of the forest stand. While the species-specific fieldwork approach allowed to improve the delineation of distribution ranges and the assessment of habitat use, the opportunistic approach pointed out to overlooked ranges but showed limited efficacy to assess the fine-grain distribution of the Middle Spotted Woodpecker.
摘要公民科学(即由志愿者参与数据收集的监测或研究计划)正在成为一种越来越常用的工具，它可能产生可靠的物种分布范围估计。在2017年和2018年，我们通过结合两种公民科学方法，评估了巴斯克地区(西班牙北部)中斑啄木鸟的细粒分布和栖息地使用情况:从互联网协作数据库收集的机会主义观察，以及经过特定物种实地调查协议培训的志愿者收集的标准化记录。在34个机会性观测中，有6个位于先前已知的分布范围之外。由于这些观察结果的可靠性难以评估，因此应该对机会性观察结果进行验证，以避免误报。在1 km2的95个UTM单元内，采用点位计数和音频刺激的方法对中斑啄木鸟的发生情况进行了调查。其中29个单位有啄木鸟的记录。结合最近的物种特异性研究，我们的结果表明，中斑啄木鸟主要发生在一个核心的连续范围内(Izki森林及其周围有69个单位)和两个较小的范围内(Montes de Vitoria 6个单位和Sierra de Entzia 5个单位)。在以前已知的分布范围中，物种特异性方法表明，啄木鸟的发生受距离核心伊兹基林的距离的负面影响，在较小程度上受林分树基面积的积极影响。特定种野外调查方法可以改善中斑啄木鸟分布范围的划定和栖息地利用的评估，而机会主义方法指出了被忽视的范围，但对评估中斑啄木鸟的细粒分布效果有限。
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Pub Date : 2021-03-19DOI: 10.3161/00016454AO2020.55.2.007
Yassine Teyar, D. Giunchi, M. Baratti, V. Falchi, M. Znari, M. Aourir
Abstract. Birds associated with steppe and pseudosteppe habitats are one of the most threatened avian communities in Europe, given their recent decline due to agriculture intensification and land abandonment. Large-scale conversion of natural and rural areas into irrigated farmlands is ongoing in North Africa, but the effects of this habitat modification on steppe bird species are not investigated. In this study, we investigated the breeding biology of the Eurasian Stone-curlew nesting in grazed steppes and irrigated farmlands in south-western Morocco. Breeding data were collected during 2017 and 2018 breeding seasons on 59 nests. Egg volume was significantly higher in grazed steppes than in irrigated farmlands (37.3 ± 2.30 cm3 vs 35.1 ± 2.11 cm3, average ± SD), possibly due to greater food availability in the former habitat. On the other hand, daily nest survival over the incubation period did not differ between habitats and it was quite high (0.85 [95% CI: 0.71–0.93]) also when compared to the data available for other regions. These results suggest that birds nesting in protected areas characterized by traditional pastoralism might find better conditions for reproduction which allow them to lay larger eggs. In addition, the ongoing process of agricultural intensification in the area does not seem to affect the likelihood of nest failure. Our data add to the few available pieces of evidence regarding the effect of breeding habitat on the reproductive biology of the Stone-curlew in the southern range of its distribution. Further data are needed in order to understand the conservation implication of our findings and, in particular, how the observed variability of egg size might affect chick quality and survival.
摘要由于农业集约化和土地遗弃，与草原和伪草原栖息地有关的鸟类是欧洲最受威胁的鸟类群落之一。北非正在大规模地将自然和农村地区转变为灌溉农田，但这种栖息地改变对草原鸟类物种的影响尚未调查。本研究对摩洛哥西南部放牧草原和灌溉农田中欧亚石鸻的繁殖生物学进行了研究。在2017年和2018年的繁殖季节，收集了59个巢穴的繁殖数据。放牧草原的鸡蛋体积显著高于灌溉农田(37.3±2.30 cm3 vs 35.1±2.11 cm3，平均±SD)，这可能是由于放牧草原的食物供应更充足。另一方面，与其他地区的数据相比，不同栖息地之间孵化期间的每日巢存活率没有差异，而且相当高(0.85 [95% CI: 0.71-0.93])。这些结果表明，在以传统畜牧业为特征的保护区筑巢的鸟类可能会找到更好的繁殖条件，使它们能够产下更大的蛋。此外，该地区正在进行的农业集约化进程似乎并不影响巢衰竭的可能性。我们的数据增加了少数可用的证据，关于繁殖栖息地对石鸻在其分布的南部范围内的生殖生物学的影响。需要进一步的数据来理解我们的研究结果的保护意义，特别是观察到的鸡蛋大小的变化如何影响小鸡的质量和存活率。
{"title":"Does the Breeding Biology of the Eurasian Stone-Curlew Burhinus oedicnemus in South-Western Morocco Differ between Grazed Steppe and Irrigated Farmland?","authors":"Yassine Teyar, D. Giunchi, M. Baratti, V. Falchi, M. Znari, M. Aourir","doi":"10.3161/00016454AO2020.55.2.007","DOIUrl":"https://doi.org/10.3161/00016454AO2020.55.2.007","url":null,"abstract":"Abstract. Birds associated with steppe and pseudosteppe habitats are one of the most threatened avian communities in Europe, given their recent decline due to agriculture intensification and land abandonment. Large-scale conversion of natural and rural areas into irrigated farmlands is ongoing in North Africa, but the effects of this habitat modification on steppe bird species are not investigated. In this study, we investigated the breeding biology of the Eurasian Stone-curlew nesting in grazed steppes and irrigated farmlands in south-western Morocco. Breeding data were collected during 2017 and 2018 breeding seasons on 59 nests. Egg volume was significantly higher in grazed steppes than in irrigated farmlands (37.3 ± 2.30 cm3 vs 35.1 ± 2.11 cm3, average ± SD), possibly due to greater food availability in the former habitat. On the other hand, daily nest survival over the incubation period did not differ between habitats and it was quite high (0.85 [95% CI: 0.71–0.93]) also when compared to the data available for other regions. These results suggest that birds nesting in protected areas characterized by traditional pastoralism might find better conditions for reproduction which allow them to lay larger eggs. In addition, the ongoing process of agricultural intensification in the area does not seem to affect the likelihood of nest failure. Our data add to the few available pieces of evidence regarding the effect of breeding habitat on the reproductive biology of the Stone-curlew in the southern range of its distribution. Further data are needed in order to understand the conservation implication of our findings and, in particular, how the observed variability of egg size might affect chick quality and survival.","PeriodicalId":50888,"journal":{"name":"Acta Ornithologica","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45301210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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